TUESDAY, May 28 (HealthDay News) -- Black men with prostate cancer wait a bit longer to begin treatment following their diagnosis than white men, a new study shows.

Researchers said racial disparities in cancer care must be eliminated so black men receive treatment for prostate cancer sooner.

"This study contributes to a growing body of studies demonstrating the disparities in care and outcomes among African-American and Caucasian prostate cancer patients in this country," study author Dr. Ronald Chen, of the University of North Carolina at Chapel Hill, said in a university news release.

In conducting the study, the researchers analyzed data from a registry that links information on cancer diagnoses with Medicare records. The study included about 2,500 black men and more than 21,000 white men diagnosed with early prostate cancer from 2004 to 2007. All of the men were treated within 12 months of their diagnosis.

The researchers found, however, that, on average, black men waited seven days longer than white men to begin treatment. Among the patients with an aggressive form of the disease, the average number of days from diagnosis to surgery or radiation therapy was 96 days for white men, compared to 105 days for black men.

The study authors also pointed out that black men are less likely than white men to undergo prostate cancer screening and more likely to be diagnosed with an advanced form of the disease. Black men also are less likely to receive aggressive treatment.

"All of these factors together can contribute to an increased rate of dying from prostate cancer in African-American compared to Caucasian prostate cancer patients," Chen said.

The researchers said more studies are needed to determine why treatment for prostate cancer is delayed for black men, and what can be done to eliminate this health care disparity.